I had my 2009 JCW with Comfort Access sitting around with the main battery disconnected for long-term storage.
When it came back time to reconnect the main battery in the car to pull iut out of storage, both keyfob remotes are unresponsive and I have to you the physical key insert to lock and unlock the car.
Testing the batteries on the remotes, they have correct voltage.

What's next? Please say there's a DIY for re-syncing the remotes to the vehicle.

- Erik

 

Is it possible the battery in the keys died during that time? Is it the original battery which came with the key in 2009? You may want to try that.

 

They should resync by inserting them in the slot and starting the car. If I remember correctly they should take a standard 2032 battery. The comfort access may need to be reprogrammed by a dealership since the battery was disconnected.